Drift Correction Methods for gas Chemical Sensors in Artificial Olfaction Systems: Techniques and Challenges

In this chapter the authors introduce the main challenges faced when developing drift correction techniques and will propose a deep overview of state-of-the-art methodologies that have been proposed in the scientific literature trying to underlying pros and cons of these techniques and focusing on challenges still open and waiting for solution

Increasing pattern recognition accuracy for chemical sensing by evolutionary based drift compensation

Artificial olfaction systems, which mimic human olfaction by using arrays of gas chemical sensors combined with pattern recognition methods, represent a potentially low-cost tool in many areas of industry such as perfumery, food and drink production, clinical diagnosis, health and safety, environmental monitoring and process control. However, successful applications of these systems are still largely limited to specialized laboratories. Sensor drift, i.e., the lack of a sensor's stability over time, still limits real in dustrial setups. This paper presents and discusses an evolutionary based adaptive drift-correction method designed to work with state-of-the-art classification systems. The proposed approach exploits a cutting-edge evolutionary strategy to iteratively tweak the coefficients of a linear transformation which can transparently correct raw sensors' measures thus mitigating the negative effects of the drift. The method learns the optimal correction strategy without the use of models or other hypotheses on the behavior of the physical chemical sensors

Genomic comparison of lactobacillus helveticusstrains highlights probiotic potential

Lactobacillus helveticus belongs to the large group of lactic acid bacteria (LAB), which are the major players in the fermentation of a wide range of foods. LAB are also present in the human gut, which has often been exploited as a reservoir of potential novel probiotic strains, but several parameters need to be assessed before establishing their safety and potential use for human consumption. In the present study, six L. helveticus strains isolated from natural whey cultures were analyzed for their phenotype and genotype in exopolysaccharide (EPS) production, low pH and bile salt tolerance, bile salt hydrolase (BSH) activity, and antibiotic resistance profile. In addition, a comparative genomic investigation was performed between the six newly sequenced strains and the 51 publicly available genomes of L. helveticus to define the pangenome structure. The results indicate that the newly sequenced strain UC1267 and the deposited strain DSM 20075 can be considered good candidates for gut-adapted strains due to their ability to survive in the presence of 0.2% glycocholic acid (GCA) and 1% taurocholic and taurodeoxycholic acid (TDCA). Moreover, these strains had the highest bile salt deconjugation activity among the tested L. helveticus strains. Considering the safety profile, none of these strains presented antibiotic resistance phenotypically and/or at the genome level. The pangenome analysis revealed genes specific to the new isolates, such as enzymes related to folate biosynthesis in strains UC1266 and UC1267 and an integrated phage in strain UC1035. Finally, the presence of maltose-degrading enzymes and multiple copies of 6-phospho-beta-glucosidase genes in our strains indicates the capability to metabolize sugars other than lactose, which is related solely to dairy niches

Rapid Screening of Alicyclobacillus acidoterrestris Spoilage of Fruit Juices by Electronic Nose: A Confirmation Study

Early screening of Alicyclobacillus spp. in fruit juices is a major applicative goal for the food industry, since juice contamination can lead to considerable loss of quality, and subsequently, to economic damages for juice producers. This paper presents an accurate study to assess and confirm the EOS507 electronic nose’s (EN) ability of diagnosing Alicyclobacillus acidoterrestris spoilage in artificially contaminated fruit juices. The authors experimental results have shown that the EOS507 can early identify, just after 24 hours from inoculation, contaminated orange and pear juices with an excellent classification rate close to 90% and with a detection threshold as low as 103 cfu/ml. In apple juice the detection threshold was about 105 cfu/ml, thus requiring longer incubation times (72 hours). PLS regression of EOS507 data can be also used to predict with fair accuracy the colony-forming units concentration of the bacteria. These results were supported by the GC/MS/MS measurements of specific chemical markers, such as guaiacol

Differential Detection of Potentially Hazardous Fusarium Species in Wheat Grains by an Electronic Nose

Fungal infestation on wheat is an increasingly grave nutritional problem in many countries worldwide. Fusarium species are especially harmful pathogens due to their toxic metabolites. In this work we studied volatile compounds released by F. cerealis, F. graminearum, F. culmorum and F. redolens using SPME-GC/MS. By using an electronic nose we were able to differentiate between infected and non-infected wheat grains in the post-harvest chain. Our electronic nose was capable of distinguishing between four wheat Fusaria species with an accuracy higher than 80%

Vecchie e nuove forme di pregiudizio: un contributo allo studio empirico degli atteggiamenti verso l’omosessualità

This study aims to investigate into prejudices towards homosexuals, even referring to traditional studies about it, already consolidated in literature, and which distinguish between implicit and explicit forms of prejudice. On this purpose, after a first exploratory stage and on the basis of existent tools, used before to investigate the ethnic prejudice (Pettigrew e Meertens, 1995; Arcuri e Boca, 1996), we created a questionnaire in three sections apt to measure blatant and subtle prejudice, positive prejudice and the degree of contact with outgroup members, respectively. This instrument has been submitted to 242 university students in their first years and belonging to different faculties. After some factor analysis we succeeded in having a definitive version of a Social Attitudes towards Homosexuality Questionnaire, composed of total 49 items in four scales. Reliability and internal coherence analysis gave satisfactory results. As it comes out of previous studies, it is possible to distinguish people in three prejudice classes. Results confirm the existence of a latent prejudice well distinguished from the blatant one and far more popular and resistant, especially in men and in subjects politically right oriented. We also found out that the existence of a positive prejudice towards homosexuals is prevailing among women. The course of studies is not significant to distinguish subjects with respect to different scales. At last, the degree of contact with outgroup members, generally not very high, relates in a negative way to both forms of negative prejudice, more to the latent one, and in a positive way with positive prejudice

Presentazione di un nuovo progetto Last Minute Market, volto a contrastare lo spreco alimentare attivato in collaborazione tra L'Assessorato Turismo Commercio della Regione Emilia-Romagna e la Facoltà d’Agraria.

Il rilancio del progetto è stato possibile grazie alla volontà della Regione Emilia-Romagna, attraverso il Servizio Programmazione della Distribuzione Commerciale, della Direzione Generale Attività Produttive, Commercio, Turismo, che nell’ambito dell’attività dell’Osservatorio regionale dei prezzi e tariffe, realizzato grazie ad un cofinanziamento del Ministero Sviluppo Economico, ha commissionato alla Facoltà di Agraria dell’Università di Bologna e nello specifico, al gruppo di ricerca del Prof. Andrea Segrè, Preside della Facoltà, uno studio volto a contrastare il rischio 'impoverimento di alcune fasce di popolazione. Fra queste attività vi è la diffusione sul territorio regionale dei "mercati dell'ultimo minuto" (Last Minute Market), basati su un sistema virtuoso che recupera le eccedenze alimentari facendole arrivare direttamente sulla tavola dei più bisognosi. In particolare la Regione avrà il ruolo di coordinare l'iniziativa mettendo assieme domanda e offerta

Why the waste? A large-scale study on the causes of food waste at school canteens

Several studies have recalled the need to reduce food waste across all the stages of the food supply chain. To undertake effective intervention strategies for food waste prevention and reduction, it is important to better understand the main causes of this phenomenon. In this study, a wide range of factors potentially related to food waste generation in primary school canteens were analysed. The data was obtained from a large-scale study carried out involving 78 Italian primary schools, where the food waste occurring at lunchtime was measured on 11,518 diners, for a total of almost 110,000 meals. The assessment included the quantification of prepared food, plate leftovers and non-served food, which were all weighed with an electronic scale and measured separately for each meal course. The food rejected by diners and the quantity of food remaining unserved at the end of the lunch were studied against a set of potential factors, including the location and size of the school, the location of the kitchen, the type of menu provided to diners, the quantity of food prepared and served. Findings obtained through the analyses of the single variables show that most of the variables have a role in influencing the quantity of food that remains non-consumed. Multivariate models were used to assess the relative importance of the factors over the quantity of food waste. The foodservice provider emerges as the most significant factor in influencing the generation of food waste at schools; other relevant factors are the amount of food prepared and the serving size, the kitchen location, the food provided for the mid-morning break, the menu composition and the geographical area